Just to muddy the waters, have you considered putting the display on one of the side walls with “L” shaped seating one leg facing the fireplace and the other the display. That might help preserve the other end of the room for gaming.
Also if you go with the end of the room for the display I don’t see why having the surrounds on the walls about 11 feet from the center of the listening position will be to far. If he plans on using a couch that will put the nearest listeners only 6-7 feet from the speaker.
If you do mount the surrounds from the ceiling they don’t have to be up high. You could buy or make mounts that will let them hang down lower.
Cheers,
Dean